The North American gypsy moth (Lymantria dispar) originated in France and was first introduced into Bedford, Mass. in 1869. Since that time L. dispar has spread through the New England area and into the states of New York, Pennsylvania, Ohio, Michigan, Delaware, Maryland, and North Carolina. These states define the generally infested area within the U.S. In addition, localized gypsy moth infestations have been identified and eradicated from nearly all of the remaining states in the U.S.
The gypsy moth strain present in the generally infested area is termed the European or North American strain. However, other gypsy strains are present in the world. Strains in which female moths have flight capability are of greatest concern due to the potential rapid spread of the strain from the point of introduction. The Asian strain is one example of a strain capable of flight. In contrast to the Asian strain, females of the European/North American strain are not capable of flight.
Recent introductions of the Asian gypsy moth strain in the U.S. have caused great concern. In addition to flight capability, the Asian strain has greater host range than the European/North American strain. Consequently, the potential economic losses from an Asian gypsy moth infestation measures in the billions of dollars. Asian gypsy moth introductions in the Pacific Northwest and North Carolina have resulted in eradication efforts costing approximately 15 million dollars. Additionally, international commerce could be affected.
Asian and European/North American strains of gypsy moth cannot be distinguished accurately by morphological differences when the samples are collected in pheromone traps due to the poor physical condition of the specimens. Therefore, an improved method of distinguishing between Asian and European/North American gypsy moths is needed.